Lock-out party-line telephone system.



A. F. ERICKSON. I

LOCK-OUT PARTY LINE TELEPHONE SYSTEM.

APPLICATION man JULY 12, 1913..

1,147,223. r v Patentd July 20, 1915.

2 SHEETS-SHEET l.

COLUM BIA PLANOORAPN OOUWASHINOTON: n4

A. F. 'ERICKSON.

LOCK-OUT PARTY LINE TELEPHONE SYSTEM. APPLICATION FILED JULY 12, 1913.

1,147,223. Patented Jul 20, 1915.

2 SHEETS-SHEET 2.

UNITED STATES EPATENT ARTHUR F. ERICKSON, OF SEATTLE, wAsHINeToN, ASsIeNoE, BY nIEEoT AN-n MEsNE ASSIGNMENTS, OF oNE-EoUETH Toi JOHN. v. BOCK AND ONE-'FQURTH1.;'J.O;GEO.JI. NONNENBAGHER, BOTH OF SEATTLE, WASHINGTON. i

Loon-OUT PARTY-LINE TELEEHONESY TEM.

Specification of Letters Patent. J

Application filed July 12, 1913. Serial No. 778,709. I

To all whom it may concern:

Be it known that I, ARTHUR F. ERICK- soN, citizen of the United States, residing at Seattle, in the county of King and State of Washington, have inventedcertain new and useful Improvementsin Look Out Party-Line Telephone Systems, the following is a specification. I

My present invention relates to telephone systems and more particularly to party lines or systems of-that character where a plurality of 'subscribers telephone apparatuses are disposed in circuit with the same line wires. In'such systems now incommon use conversation among two parties may be overheard by a thirdparty through the receiver and at the annoyanceto'parties using the telephone apparatus resulting from a third party attempting to communicate with thecentral office during conversation between the first mentioned parties.

The principalobject of my invention is to provide apparatus whereby when two parties ontheir respective 'lines are conversing, a third party on either line cannot overhear isujch' conversation or throw resistance in cir- 'cuit, as commonly results from the lifting of the receiver on apparatus 'nowln use and thereby 'decreasingthe audibleness of: the conversation. v i

Further objects of the il'lVGIltlOIl areto provide apparatus whereby the resistance necessary for successful operation thereof is, as'far as poss ble, unlform to the conductingof the current to any station in circuit.

'Still further objects of my invention are to provide a lock-out device which may be easily installed in connection with existing apparatus without modification or alteration of thesame apparatusyadevice of'the character described requiring no auxiliary apparatus or device atthe central oflice, or

at a any of the I subscribers apparatuses, thereby enabling itsinstallation to be accomplished at verylow cost and its maintenance reduced to a minimum; alock-out device which is protected: from inclement weather so-that'i t may be'disposedexteriorly of the building; containing the telephoneapparatus andlthusbeingunaccessible "of I which for tampering by unauthorized persons A T and, to provide such a device that, including electro-magnets in parallel, will prevent overbearing of the'conversation between the two, parties-by a third party, by in'duction between the said electro-magnets; Y

t Other objects ofthe'invention Wlll appear in the following detail description, taken in connection with the accompanying edrawings, forming a part of "this specification, and in which drawings I Figure 1- is af-diagrammati c view of a party line telephone system embodying my invention. Fig. 2is a detail viewpartly in plan and partly in section, showing the lockout device. Fig- 31s 'a perspectiveview'of the look-out device. Fig-4 is a detail di'ae grammatic view 'of a portionof the appa ratus shown inthe diagram-in Fig. 1. -F-ig'.; L

5 is a modification of therdiagram disclosed 1 o in Fig.-1 p In the drawings, where;-similar characters refer to similar parts,.A and B-designate line Wires, (1 O the central ofiic'e, D sub:v

scribers telephone apparatus and E "lock- -out devices.

' Each lock-out'device' includescoresfiand A 7 supported, as through cylindrical casings 8 in'insulate'd relation, by a; suitable base-9 which latter, in itself, may -becomposed-of insulative material. Coils ;:of conducting material 10, to provide {aneleetro-magnet,

are disposed'about core 6 -and-si1nilar coils 11, are disposed about" core -7forthe same purpose. I

The lead 12 0f coil 10 is fin-conducting communication with onesection of line'w-i're' B while the otherl'ea'd 13 is in conducting connnunication with the core 7. One"lead 14 of the coil'll is'in' conducting communi cation with the subscribers telephone apparatus D, while the other lead raisin-con:

ducting communication with the core-e; For coaction with the core 6 Iprovidegan armature 16 and'for core 7, an armaturef ll.

shape and are normally held-retracted 'from These armatures are preferably ct -disk able manner, and as disclosed in the drawing, the springs 18 contact with the walls of the cylindrical casing 8 which accommodates the electro-magnet and its armature, and being of magnetic metal, place the armature in direct magnetic circuit with the core as clearly shown in Fig. 2 of the drawings. The casings 8 serve the dual purpose of protecting the electro-magnet from inclement weather as well as forming a conducting means between the armature and its core being so constructed that they carry all possible magnetic lines of force from one of the electro-magnets to its opposite pole through the armature as agent, and also prevent-induction between the two electro-magnets which might otherwise enable a third party to overhear the conversation between two other parties although such would be only faintly audible. These springs 18 normally position their respective armatures in electrical engagement with the contacts 19 which, as disclosed in the drawings, are insulated from cylindrical casings 8 and covers the open ends thereof. This contact 19 is placed in conductive communication with another section of line wire B as through lead 20. Each subscribe'rs telephone apparatus includes the usual transmitter 21, re ceiver' 22 and-receiver hook 28, and it is well known that the raising of this receiver from its hook places the particular apparatus in circuit with the line wires of the telephone system. The lock-out device may be dis posed preferably at terminals of distribution of drops such as inthe building or at the telephone pole from which the drops are taken to the building containing the station.

It is obvious from the foregoing that the circuit for each apparatus D includes the wire B, lead 20, contact 19, armature 16, coil 11, and'lead 14:, as well as any suitable conductor 24: in communication with the other line wire A. v

The operation of the system as diagrammatically disclosed in Fig. 1 is as follows: It is welllmown that, in telephone systems of the character described, a resistance R is normally placed in circuit with the line wires A B while such are not in use for the transmission of undulatory currents by which the sounds of the voice are transmitted. Therefore, the current through the coils 10 and 11 is not such as to magnetize their respective cores sufficiently to draw the respective armatures of the cores except when such resistance R is thrown out of circuit and one of the receivers 22 is raised subscriber for apparatus designated 2, the

central office O O is called in the usual man ner and the operator thereat proceeds to give the necessary audible signal at the various apparatuses 1, 2, 3 and 1, or selectively if suitable apparatus is provided, assuming that it is a four-party line, designated for subscriber 2. The subscriber in question communicates with the calling subscribers apparatus. This placing of the subscribers apparatus in operative relation one to the other causes the resistance hereinbefore referred to to be removed and the core 7 of the device E adjacent the apparatus designated 2 is energized sufliciently by the current to draw its armature 17 from engagement with contact 19 and the circuit is broken at this point. Likewise the core 6 of the other device E intermediate the device in question and the central office are energized so as to draw the respective armatures 16 from engagement with contact 19, so that the current is broken at each of the apparatuses 3 and 4t, and the circuit for apparatus 1 is broken by the holding of the armature 17 at the device E adjacent the apparatus 2, from engagement with the contact 19.

If a party on the subscribers line desires to call a party on the same line, such as subscriber 4, desiring to call subscriber 2, the former proceeds to call the central oflice and after having given the number is instructed to replace the receiver until the party wanted is called. The operator then proceeds to give the audible signal at the apparatus designated for subscriber number 2.- During this operation the resistance R is thrown in circuit with the mains A and B to render the electro-magnet of devices E without power to move their respective armatures. The subscriber recognizing the call raises the receiver and the conversation is proceeded with. The resistance R is thrown in and remains so until such conversation, over the same subscribers line, is brought to a close as will be indicated at the central oflice board. As previously stated, because of such resistance the electro-magnets of devices E are without power to move their respective armatures although there is sufiicient current to provide for successful operation of devices D. A conversation may be heard by a third party when two parties on the same line are in conversation, however, in practice it seldom occurs that two parties on the same line carry on a conversation one with another, so that such is without serious objection. It is to be understood, however, that, assuming subscriber 3 to raise the receiver to communicate with C. 0., that when G. 0. answers, the resistance is relieved and none of the other subscribers can get into communication with C. O. without such resistance ispag'ain thrown in circuit, since the relieving of resistance, other than that, of *course, in the'line wires and devices E and D,.permits of suchenergizing of-the electro-magnets of the four devices as to draw the armatures and break the circuits as previously described.

Referring now to the diagram in Fig. 5, I have disclosed a system whereby the object set forth in the third paragraph of this specification is accomplished. This system is particularly adapted for use for a fourparty line system and the idea is to conduct a current through the two devices E regardless as to whether apparatuses 1, 2, 3 or 4 is brought into use. For instance, assuming that apparatus 4 is called the cores 7 of the devices E will be magnetized as soon as the resistance is relieved and a break will occur at their respective armatures, the current being conducted successively through wire A; wire 24; apparatus D; thence to wire 14; to the adjacent device E. It is then conducted through coil 11; about core 7, and having energized it causing a break at the armature of 7; through wire 15; core 6; contact 19, to the line wire B. Then through wire B to the next adjacent device,

E following through coil 11 energizing core 7 and making a break at its armature; through wire 15; core 6; contact 19; and back to C. 0. through wire B. The break at the armature of core 7 of devices E mentioned cuts out apparatus 1, 2 and 3 so long as the resistance is not thrown in circuit. It is of course understood that all of the wires 24 are inactive except the one connected with the apparatus in use since the circuit is always normally broken at apparatus D. This will lock out apparatuses 1, 2 and 3 unless the call has been for a party on the same line whereupon the said resistance renders all of the electro-magnets of devices E inoperative for the purpose intended. Likewise if the circuits of the various other apparatuses are traced it will be found that the raising of the receiver of any other apparatus will cause a circuit to be conducted through the former two devices E in contra-distinction to the conducting of a current to the other three devices E in the system as disclosed in the diagram in Fig. 1 when their apparatuses 1 or 2 is brought into use.

Changes in detail may be made without departing from the spirit or scope of my invention; but;

I claim 1. A lock-out device for party line telephone systems comprising in combination, two electromagnets the one lead of the coil of each being in electrical conducting communication with the core of the other electro-magnet, an armature for each core normally disposed retracted therefrom, and a contact with which both of the said armatures are normally electricaLconducting cornmunlcatlon, sald contact being otherwise insulated from the cores of saidelectro-rnagnets.

v2. A lock out'device for party line tele phone systems comprising in combination, two electro-magnets the one lead of the coil of each being in electrical conducting communication'with the core of the" other I electro-magnet, an armature for each core normally dlsposed retracted therefrom, and

means for conducting an electric current from each of said individual armatures only when it is in a normal position.

3. A look out device for party line telephone systems comprising in combination, two electro-magnets, the lead of the coil of each being in electrical conducting communication with the core of the other electro-magnet, an armature for each core nor mally disposed retracted therefrom, a casing of magnetic metal about each electromagnet and in direct magnetic circuitawith the core and armature thereof, a contact conducting an electric current through each individual armature only when it is in a normal posltion and closlng the ends of sald casings, and means for insulating said contact from said casings.

4. A look out device for party line telephone systems comprising in combination, two electro-magnets, the lead of the coil of each being in electrical conducting communication with the core of the otherelectro-magnet, an armature for. each core normally disposed retracted therefrom, a cylindrical casing of magneticmetal about each electromagnet in directmagnetic cir-,

cuit with one pole of the core of its respective electro-magnet and having an open end adjacent the other pole thereof, an armature for each electro-magnet disposed within its cylindrical casing adjacent the open end thereof, means for holding each armature normally retracted from its respective core,

and a contact with which the said armatures phone apparatus of each pair, and each of.

said lock out devices being adapted, when the receiver circuit of any particular telephone apparatus is closed, tolock out the other telephone apparatus of the pair, and

a third lock-out device .disposed in the circuit of theline Wire intermediate the pairs of telephone apparatuses, adapted, When In testimony whereof I aflix my signature tlile receiver circuitfof any particuiar (gelein presence of two Witnesses. p one apparatus 0 one pair is c ose to lock out the other pair of telephone appara- ARTHUR ERIOKSON 5 tuses, from the circuit of the line Wires, Witnesses:

substantially as and. for the purpose set L. A. PRICE, forth. RICHARD B. OWEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

